Cognitive Disability and Moral Status

Why are cognitive disability and moral status thought to be
sufficiently connected to warrant a separate entry? The reason is that
individuals with cognitive disabilities have served as test cases in
debates about the moral relevance of possessing such intellectual
attributes as self-consciousness and practical rationality. If a
significant portion of human beings lacks self-consciousness and
practical rationality, then those attributes cannot by themselves
distinguish the way we treat cognitively developed human beings from
the way we treat non-human animals and human fetuses. If we cannot
experiment on or kill human beings who lack those attributes, then the
lack of those attributes alone cannot be what justifies animal
experimentation or abortion.

For the most part, the philosophers who have considered these claims
were not primarily concerned with the treatment or moral status of
cognitively disabled human beings—they sought to challenge
existing practices toward fetuses or animals, or the rationales for
such practices. But those claims have significant practical
implications for cognitively disabled human beings. If the
justification for treating living beings in certain ways does
rest to some extent on their possession or lack of intellectual
attributes, then it may be acceptable to treat cognitively disabled
human beings in ways that it would be unacceptable to treat
cognitively nondisabled humans. This implication, a kind of
philosophical blowback from the debates on animal rights and abortion,
has become the subject of sustained controversy in applied ethics.

Philosophers who question the moral status of human beings with the
most significant cognitive disabilities often compare them to animals
claimed to have similar or greater cognitive abilities (McMahan 1996,
2002, 2009; Singer 1993, 2009; and Wilkinson 2008 in Other Internet
Resources). Some critics find these comparisons unnecessary and
offensive (e.g., Carlson 2009; Carlson and Kittay 2009). The
philosophers who make such comparisons emphasize contrasts like the
following: Vast numbers of chimpanzees and other “higher”
primates are used in painful and often lethal research for the benefit
of human beings. Although there are strong objections to specific
primate research programs and research on specific primates, there is
broad agreement that most primate research is acceptable if it has the
potential to contribute significantly to human health, and if the
harms and risks to the animal subjects are minimized. In contrast,
cognitively disabled human beings cannot be enrolled in potentially
harmful research unless they are likely to benefit, the risk of harm
is negligible, and their legal representatives consent to their
participation. They enjoy these protections even if they are no better
able than non-human primates to understand the aims of the research or
to consent to
participation.[1]

The debate over the moral status of individuals with the most severe
cognitive disabilities also raises difficult methodological issues
concerning the reliance on intuitions, convictions, and considered
judgments in assessing moral arguments. Some philosophers would deny
that any argument should persuade us to abandon our conviction that it
would be terribly wrong to subject a human being cognitively incapable
of consent to painful and dangerous experimentation of no possible
benefit to him (e.g., Kittay 2008). Two philosophers have adapted G.E.
Moore’s “proof” of the existence of the external world (see
Entry on
George Edward Moore)
to claim that we are more confident of the truth of the proposition
that all human beings are morally equal, and morally superior to other
animals than of the validity of the arguments denying it (Curtis and
Vehmas, 2016a, 2016b). Other philosophers reject the application of
Moore’s argument to moral status (Lachlan, 2016; Roberts
forthcoming); more broadly, they insist that even firm convictions
about moral status cannot be immune from critical scrutiny, especially
if they appear to conflict with other deeply held convictions (McMahan
2007). Still others deny such convictions any presumptive weight or
authority (Singer 2005).

Finally, in addressing the moral status of cognitively disabled humans
in a separate entry, rather than in a general entry on disability, we
are not endorsing a controversial “exceptionalism” about
cognitive disabilities—a view that regards them as fundamentally
different from other kinds of impairment (see
Related Entries below).
Our reason for limiting ourselves to cognitive impairment is
dialectical: there is currently no debate about the moral status of
individuals with non-cognitive disabilities. We know of no serious
philosopher who argues that people who cannot see, hear, or use their
legs, or who experience frequent depression or hallucinations, have
lower moral status than people without such disabilities. Admittedly,
some philosophers claiming to regard humans with physical or
psychiatric disabilities as having the same moral status as
nondisabled humans also take positions that other philosophers see as
inconsistent with a commitment to equal moral status. One notable
example is Rawls’ (1971) exclusion of people with physical
disabilities from the Original Position on the assumption that they
are not fully cooperating members of society. Another example is the
defense of “quality adjustment” in allocating scarce
healthcare resources, which discounts the life-years of people with
disabilities to reflect their supposedly lower quality of life
(Williams 1987). But whether or not these positions are consistent
with the recognition of full moral status, their proponents insist
that they are; they do not attempt to argue against the equal moral
status of people with physical or (most) psychiatric disabilities. By
contrast, the moral status of human beings with cognitive disabilities
has become a subject of intense debate among philosophers, applied
ethicists, and disability scholars (for a recent discussion, see
Carlson and Kittay 2009).

We will proceed as follows. We will first characterize the human
beings who are the subject of the debate on moral status—those
with what we will call “radical cognitive disabilities.”
After discussing the ways in which humans are classified as
cognitively disabled, we will describe the narrower category of humans
whom the debate concerns. To be clear, this is a group of humans
stipulated to exist rather than classified by empirical procedures. We
will note the difficulty of separating claims about such stipulated
individuals from claims that some actual individuals satisfy that
stipulation. Next, we will characterize the concept of moral status,
describing its structure and function. We will then outline the
principal differences in how that concept is understood, particularly
its “inclusion criteria”—the criteria for ascribing
what we will call “full moral status,” the status
attributed to cognitively nondisabled adult human beings. (In calling
that moral status “full,” we do not intend to take sides
in the debates over whether there can be any higher moral status.) We
will identify one family of moral-status accounts—those basing
possession on individual attributes—as the primary, though not
the exclusive, source of the challenge addressed in this entry: the
claim that some human beings lack full moral status. After outlining
those accounts, we will review several ways of meeting the challenge:
1) basing full moral status on individual attributes shared by a
greater proportion of human beings; 2) adopting secondary grounds for
the possession of full moral status—by “courtesy” or
by “proxy”; 3) rejecting individual attribute accounts in
favor of accounts that base the full moral status of all human beings
on their species membership or their humanity.

There is, not surprisingly, disagreement about how to define cognitive
or intellectual disability. (We will use these terms interchangeably,
ignoring, unless specifically relevant, their apparent differences in
breadth and emphasis.) There are competing psychometric and functional
definitions, based respectively on standard deviations from the mean
score on intelligence tests and on “significant limitations both
in intellectual functioning and in adaptive behavior, which covers
many everyday social and practical skills” (American Association
of Intellectual and Developmental Disabilities, 2011). For this entry,
we will consider individuals defined as cognitively disabled in
functional terms, because our interest is in the moral relevance, if
any, of the absence or substantial limitation of critical cognitive
functions. These limitations are more likely to be captured by
functional than psychometric tests, though as we discuss later, the
former as well as the latter may fail to detect significant
intellectual capacities. We will not assume that, or examine whether,
individuals with psychometrically-defined “severe” or
“profound” intellectual disabilities are functionally
disabled in this way.

As noted, this entry will focus on human beings with “radical
cognitive
disabilities”[2]
— disabilities in intellectual function and capacity that limit
or preclude the development of one or more attributes believed to
confer full moral status. Among those attributes are the consciousness
of oneself as a temporally-extended being; practical
rationality—the capacity to govern one’s actions by
reasoning about how to act; and the capacity to make and respond to
moral demands. (We will often abbreviate the list to
“self-consciousness or practical rationality” without
making any assumptions about the centrality or relationship of the two
attributes.) These attributes, as well as others held to be required
for full moral status, may be possessed by different subsets of human
beings, and the relationship among such attributes is a matter of
considerable dispute. This dispute, however, is best deferred to a
fuller treatment of the grounds of moral status; we will discuss them
only to the extent that they bear on the moral status of human beings
with significant cognitive disabilities.

The category of “radical cognitive disability” is
stipulative. We do not start with the assumption that any specific
human being falls into that category, or even that some human beings
do. Eva Kittay (2005) has argued that there is no reason to assume
that any human beings are radically cognitively disabled, in the sense
we are using the term. Jeff McMahan (2009) has countered that the
existence of such human beings is very likely: given the continuous
nature of fetal and infant neurological development, it is very likely
that some human beings are radically disabled because their
development has ceased or been interrupted at points where they have
not yet acquired morally relevant capacities. Even if McMahan’s
“existence argument” for radical impairment is correct,
however, it does not remove the daunting uncertainty of attributing
radical cognitive impairment to any actual human being.

This uncertainty arises in part from a lack of clarity and consensus
about what would count as adequate evidence of self- and
other-awareness and practical rationality. To resolve that question,
it is necessary to confront not only interpretive ambiguities in
making inferences about the content of other minds, but conceptual
issues about what it means to possess critical cognitive functions.
Similar issues are raised in the debate about animal consciousness
(see the Entry on
animal consciousness),
but there is also disagreement about whether the kinds of evidence
adduced for and against the cognitive capacities of animals are
equally relevant in assessing the cognitive capacities of human beings
(Kittay 2005; McMahan 2002, 2005, 2008).

The primary reason for restricting the entry to radical cognitive
disability, like the reason for restricting it to cognitive
disability, is dialectical. Few contemporary philosophers would deny
that human beings with mild or moderate cognitive disabilities have
the attributes required for what we call “full moral
status.” Philosophers who see self-consciousness and practical
rationality as necessary for that status generally recognize that
mildly and moderately disabled humans possess those attributes, and
possess them to the extent necessary to reach the threshold set by
their accounts of full moral status (see
Sec. 2.1).

By stipulating a category of human beings with radical cognitive
disabilities, we seek to avoid difficult empirical issues about the
extent to which individuals classified as having serious cognitive
disabilities actually lack the psychological functions held to confer
moral status. Even the most direct assessments of these functions may
fail to recognize atypical, especially nonverbal, forms of cognitive
functioning. And with the possible exception of extreme cases like
anencephaly, there are formidable difficulties in inferring a lack of
cognitive capacity from a lack of specific behavior or brain activity.
As recent work on intellectually conscious states has revealed (Wannez
et al. 2017, Real et al. 2015), some psychological capacities are
difficult to detect neurologically or behaviorally.

We recognize that there are objections to the use of stipulation to
sidestep these difficult empirical issues. Disability scholars insist
that philosophers must recognize that the terms they use will
inevitably be taken to refer to actual human beings, so that they
cannot stipulate away concerns about hurt and misinterpretation
(Kittay 2005; Wong 2007). Moreover, the prevalence of individuals who
actually satisfy their stipulations has relevance to morally
significant policy issues, such as the costs and benefits of more
inclusive educational practices. Nevertheless, we will rely on the
stipulation that we have made about radical cognitive disability, in
part because the assumption that some human beings are radically
disabled is shared by many of those who argue for the full
moral status of all human beings.

We will discuss only radical cognitive disabilities that are
congenital or early-onset. The question of how moral status is
affected by the loss of important cognitive functions is a
distinct one, both for those who believe such functions confer moral
status and those who do not. Concerning the former, the question is
whether moral status can survive the loss of the functions on the
basis of which it was conferred. For those who deny that moral status
requires the possession of those functions, their loss may still raise
important questions about personal identity, and about the
first-person authority of the earlier, nondisabled self over the
later, disabled self. The treatment of “once-competent”
individuals in minimally conscious states, or with severe dementia,
thus raises distinct issues about the impact of psychological
discontinuity or loss of mental function on the relationship of human
individuals to their past or future selves. There has been a
protracted controversy, and a large literature, on these issues
(Dresser 1995; Dworkin 1994; Stone 2007); they deserve separate
discussion.

“Moral status” is not part of the shared vocabulary of all
ethical theories. An act utilitarian, for example, has no more use for
that concept than for “respect,” “rights,” or
“inviolability.” For a theory that accorded weight to
beings only in proportion to the utility they enjoyed or produced, the
concept of moral status would be relevant only in the indirect sense
that its use would affect aggregate utility in various ways. For
example, the negative utility that might result from denying some
human beings full moral status might support a policy of treating all
human beings as if they had full moral status (see
Sec. 4).
On such a theory, the most salient moral property of an individual is
her capacity to occupy states that can be characterized as
“good” or “bad,” the most obvious being
pleasure and pain. The possession of such a capacity gives an
individual a morally considerable interest in occupying or avoiding
such states. Moral considerability is: 1) continuous, in that the
degree of moral considerability that a being possesses varies in
proportion to the strength, character, and number of its interests;
and 2) asymmetrical, in the sense that a being might have moral claims
on others without others having moral claims on it.

When non-utilitarian philosophers discuss “moral status”
of a type of being, they are generally using a more categorical notion
than moral considerability. They generally understand moral status as
a threshold concept and a range concept. Beings that fall below a
minimum level—the threshold—of a status-conferring
attribute like rationality lack a certain kind of moral status despite
possessing the attribute to some degree. And all beings that fall
within the “range”—that reach the threshold level of
the attribute—have the same moral status regardless of how far
they exceed that threshold. (The term “range concept”
comes from Rawls; his example is of points within a circle, all of
which are equally “inside” despite varying distances from
the circumference.) More controversially, moral status is sometimes
regarded as symmetrical: a being must be able to have moral claims
made on it (and hence be capable of responsibility) as well as being
able to make moral claims on others. A symmetry condition would
exclude any human being lacking the capacity to have moral claims made
on them—not only individuals with radical cognitive impairments,
but infants and young children as well.

Not all writers on moral status treat it as both a threshold and range
concept. Both features of the concept have been challenged, and the
concept itself has been criticized as hierarchical and elitist (Birch
1993). Several philosophers have argued for treating moral status as a
matter of degree, so that a being’s moral status varies
proportionately with its morally-relevant attributes (Perring 1997;
DeGrazia 2008). These proposals avoid uncomfortably sharp dichotomies,
but they have a revisionary character. Even if commonsense morality
recognizes some gradations in moral status, well-established social
practices such as animal research assume discontinuities. Moreover,
even if common sense could be reconciled to gradations below the
threshold (which would thereby become less of a threshold), it would
balk at recognizing gradations above it, thereby abandoning moral
status as a range concept.

More comprehensively, Mary Ann Warren has proposed a multi-criterial
account of moral status, in which it is neither a range nor a
threshold concept. For Warren, the moral status of a being varies with
the degree that it possesses the status-conferring attribute (Warren
1997).[3]
But Warren maintains that “full moral status” is both a
threshold and a range concept; beings with moral agency enjoy the
same, highest moral status regardless of the degree to which they
possess the attributes needed for moral agency. As noted earlier, we
will use the term “full moral status” to refer to the
moral status that is generally accorded to cognitively nondisabled
human adults, without assuming that there can be no higher status.
“Full moral status” is thus roughly synonymous with
“personhood” as that term is used in debates about whether
fetuses, or higher primates, are persons.

The issue of moral status, and which beings have full moral status,
has become important because of its bearing on the rights and
treatment of those beings. “Moral status” and “full
moral status” are not intended as honorifics; their ascription
to a being entails that it enjoys rights that other beings, lacking
that status, do not. The particular rights entailed by full moral
status may, however, differ on different moral theories. Two theories
with the same concept of moral status and the same criteria for
assigning it (see
Sec. 2.2)
may associate full moral status with different rights or rights of
different strength. One theory might, for example, hold that beings
with full moral status may never be used as mere means, whereas
another might hold that they may be so used in certain emergencies.
There is, though, only partial independence between the formal
character of and criteria for moral status, on the one hand, and the
rights entailed by such status, on the other. For example, it would
seem implausible for a theory to recognize a categorical notion of
moral status while rejecting any notion of rights. An account of moral
status need not deny all rights to beings falling below the threshold
it sets; they will merely lack the same package of rights possessed by
beings above that threshold.

Two philosophers (Sachs, 2011; Silvers, 2011) have questioned the
utility of the concept of “moral status.” Sachs argues
that claims about moral status are unnecessary and confusing, because
the debate is really about the specific attributes needed to justify
or ground specific rights. Silvers offers an even harsher critique.
She charges that proponents of both psychologically and biologically
based criteria (see
Sec. 4,
Sec. 5, below) neglect gradations in relevant characteristics
and overlook the potential to display or develop those
characteristics, resulting in unwarranted exclusion. As an
alternative, Silvers proposes an account of justice that, avoiding
prior assumptions about capacity, seeks to include as many beings as
possible within a scheme of social cooperation.

Although moral status claims may well obscure more often than they
enlighten, they do not, however, merely concern the grounding of
specific rights in specific attributes. First, as noted above,
theories that share the same criteria for full moral status may differ
in the rights they associate with that status, and vice-versa.
Moreover, even if Silvers is correct about the exclusionary tendencies
of moral status notions, the prior question remains of whether their
threshold and range features can be justified. How can the small
differences in morally-relevant attributes that place a being above or
below the threshold ground large differences in the package of rights
and immunities that being possesses? How can all cognitively normal
humans have the same package of rights and immunities despite
differing greatly in the attributes that place them above the
threshold? Those who defend the standard concept of moral status need
a moral theory to underwrite its range and threshold features; those
who attack it need to deny that any plausible theory could do so.

The central question in the debate over the full moral status of human
beings with radical cognitive disabilities concerns the type of
attributes on which moral status is based. Most of those who deny or
question the full moral status of all human beings insist that moral
status must be based exclusively on attributes or properties of the
individual; those attributes must be identifiable by a biological or
psychological inventory of that individual, with no reference to the
biological or social environment it inhabits. For example, it would be
possible to assess an individual’s self-consciousness or
practical rationality knowing nothing about its fellow creatures
(although the assessment itself might have to be done by
self-conscious and practically rational creatures). In contrast, we
could not ascertain an individual’s species membership or social
relationships without knowing a great deal about the world it
inhabited. We will call accounts based solely on individual attributes
“individually-based”; we will label
“group-based” those accounts based on facts about the
individual’s membership in a biological or social group, or her
relationship with other members of that group. Those facts may concern
the individual’s biological origins, the typical or average
characteristics of a biological or social group to which she belongs,
or her actual relationships with other individuals. Although some
individually-based accounts concern an individual’s capacity or
potential to form relationships of certain kinds with other
individuals, it is that capacity or potential which confers moral
status, not the existence of such relationships.

Those who insist that moral status must be based on an
individual’s own attributes, that it cannot depend on the
accidents of birth or the vagaries of biological classification, are
also likely to insist that an individual’s claims on others
cannot depend on whether those others happen to be members of the same
species or communities. In this view, full moral status must not only
be independent of external circumstances, but must be universally
recognized. Although some group-based accounts may require that a
being’s full moral status be universally recognized, others see
full moral status as group-relative (see
Sec. 5.1).

In comparing accounts of moral status, it is important to note two
possible differences between such accounts. First, they may propose
different conditions as sufficient for full moral status. Some
accounts, for example, claim that membership in the human species is
sufficient for that status. Second, they may offer different
explanations of how the satisfaction of those conditions grounds or
warrants full moral status. For example, even if being a Homo sapiens
suffices for possessing full moral status, there may be different
rationales for why it is sufficient: 1) because it is in the
nature of Homo sapiens to be rational; 2) because the
rational nature of the species requires respect for all of its
members, rational or not; or 3) because members of the same species
have a duty of partiality to each other, regardless of their
individual attributes. Thus, the two accounts ground moral status in
the same relational property—membership in the human
species—and they make membership a sufficient condition for full
moral status. But they use the fact of species membership differently
in justifying moral status. They might also associate different rights
with full moral status, in accordance with their different ways of
grounding it. And, as discussed in
Sec. 4,
they may have different implications about who is required to
recognize or respect an individual’s status.

Individually-based accounts generally take cognitively normal adult
human beings as their paradigm and pick out one or more of their
attributes as sufficient for the moral status they
enjoy.[4]
These accounts identify overlapping clusters of psychological and
cognitive attributes—self-consciousness, awareness of and
concern for oneself as a temporally-extended subject; practical
rationality, rational agency, or autonomy; moral responsibility; a
capacity to recognize other selves and to be motivated to justify
one’s actions to them; the capacity to be held, and hold others,
morally accountable. These attributes pick out different subsets of
human beings. Some self-conscious humans, for example, may lack the
capacity to be held morally accountable. But individually-based
accounts may differ less in the range of beings to whom they accord
full moral status than in the ways they regard those attributes as
grounding that status.

One approach holds that psychological attributes confer moral status
by virtue of the interests to which they give rise. This approach
treats psychological attributes as the basis of interests that we have
a prima facie obligation to advance, or at least not to
thwart—an obligation whose strength varies with the strength and
other features of those interests. The capacity to feel pain grounds
an obligation to avoid its infliction; the capacity to anticipate and
dread as well as feel pain may ground a stronger obligation. But if
additional psychological capacities merely increased the strength of
the interest, and the corresponding obligation to advance or not
thwart it, an interest account would not provide a basis for a moral
status threshold (McMahan 2002).

An account that accorded interests moral weight in proportion to their
strength would not require a notion of moral status, even if beings of
a particular type tended to have stronger interests. Thus,
philosophers who account for our differing obligations to beings of
different species in terms of their unequal interests tend to regard
“moral status” as an unnecessary or inert notion (Harman,
2003, 187), or to conclude that all beings with interests (for which
sentience is often thought necessary) have equal moral status (Rossi,
2010). This denial of different levels of moral status, however,
licenses the unequal treatment of human beings with the most severe
cognitive impairments if they are assumed to have weaker interests,
especially in survival. Thus, it offers cold comfort to defenders of
the moral equality of all human beings.

More categorical interest-based approaches ground moral status in the
capacity to experience oneself as a temporally-extended being whose
life can go better or worse (Singer 1993; Tooley 1983) or to value
one’s own existence (Harris 1985; Newson 2007). Individuals
having such capacities can care about and value their future lives in
ways that individuals lacking those capacities cannot, giving them a
qualitatively weightier interest in those lives (McMahan 2002).
Whether or not such capacities can account for the threshold and range
features of full moral status, their adoption as criteria appears to
deny that status to human beings with the most significant cognitive
impairments.

A second approach, derived from or inspired by Kant, sees moral status
in terms of the respect demanded by the possession of one or more
attributes, such as autonomy or moral responsibility (e.g., Korsgaard
1996). This approach regards the possession of an autonomous will as
conferring dignity and demanding respect, so that a being with such a
will must not be treated as a mere means, but as an end. This Kantian
conception of full moral status is often regarded as a paradigm, in
identifying an attribute that does not vary
continuously,[5]
and whose possession appears to have clear moral implications. The
threshold for moral status set by many Kantian accounts is a high one.
If those accounts regard the capacity for autonomy as the threshold
for full moral status, and if they understand that capacity as
grounding moral status in moral responsibility, then since
“there is nothing for which we would hold human infants or
severely cognitively disabled adults morally responsible, it is
argued, such humans must lack Kantian moral status” (Kain 2009,
66).[6]
Even if humans need not be held morally responsible to enjoy full
moral status, many would still lack the capacity for autonomy that
seems essential on any Kantian account.

A third approach, associated with contractualism, sees moral status in
terms of the attributes needed for membership in a moral community, or
for participation in relationships of mutual recognition and
concern.[7]
It is the capacity for forming such relationships, not their actual
formation, which grounds full moral status. A cognitively normal human
being would have such status even if he were abandoned on a desert
island. This approach, the most clearly symmetrical, treats certain
attributes as necessary for moral status not because their mere
possession generates moral obligations, but because they are
requisites for the kind of relationships in terms of which the
proponents of this approach understand moral obligations. This
requirement may appear to give cognitive and psychological attributes
a more instrumental role than they are assigned by the second
approach. It’s not that their mere possession demands respect,
but that they enable their possessors to form relationships of which
mutual respect is an integral part.

Though relationship-based accounts differ conceptually from
respect-based accounts, they differ little in practical terms. They
will identify different human beings as having full moral status only
if humans can have the cognitive or other psychological capacities
necessary for respect while lacking the empathy or motivation
necessary for membership in a moral community (or vice-versa). For
example, a moral-relationship account might exclude psychopaths. But
so might a respect-based account, if it denied psychopaths autonomy
because they lacked the capacity to be motivated by a sense of duty,
or more broadly, a capacity to recognize and act on moral reasons (see
Shoemaker 2007). A respect-based account might also exclude
psychopaths if it attributed their moral deficits to severe
disabilities in practical rationality. Relationship-based accounts
would, like Kantian ones, appear to set a very high threshold for full
moral status. The greater the moral accountability demanded by the
relationship, the more difficult it may be to claim that human beings
with radical cognitive impairments are capable of participation.

One challenge for all of these accounts is to identify an attribute or
attributes that can explain, or at least be reconciled with, the
threshold and range features of the prevailing concept of moral
status. The difficulty presented by a threshold is that it imposes
moral discontinuity over psychologically continuous attributes. In
contrast to the possession of a soul, for example, practical
rationality, moral responsibility, and most other individual
attributes claimed by contemporary accounts to ground moral status,
appear to come in degrees. Looking at the development of an infant,
the acquisition of these attributes appears to be gradual, even if its
pace is uneven. And yet our judgment of moral status appears
categorical—an individual either has full moral status or lacks
it. The categorical character of moral status is also clear above the
threshold. We do not think that the more highly intelligent, more
deeply self-conscious, or more fully autonomous among us have a higher
moral status than the rest, even those near the edge. The challenge of
justifying this range feature of full moral status is closely related
to the challenge of justifying the threshold—why should
differences above the threshold be morally insignificant when the
threshold itself is so significant?

If full moral status is determined by the possession of any of the
cognitive attributes discussed in the last section, then that status
will be enjoyed by some non-human animals and—more
problematically—almost certainly lacked by some humans. Most
proponents of individually-based attribute accounts welcome the
implication that we cannot justify existing disparities between our
treatment of “higher” animals and cognitively disabled
human beings, and many argue that those disparities are better reduced
by raising our standards for non-human animals than by lowering them
for cognitively disabled humans.

The optimal point of convergence … requires that traditional
beliefs about animals be more extensively revised than traditional
views about the severely retarded. (McMahan 2002, 230)

But full convergence, as McMahan recognizes, would have disturbing
implications even if it were achieved entirely by upgrading the
treatment of nonhuman animals:

[T]he preservation of the traditional view [that it is seriously wrong
to kill an anencephalic infant] will commit us to the conclusion that
it is seriously wrong to kill an animal that altogether lacks the
capacity for consciousness. And this is unacceptable. (2002, 230)

Convergence at a significantly lower level would have equally
unacceptable implications. For example, it would permit the use of
radically impaired human beings in any research, however harmful, for
which the use of animals with comparable cognitive capacities was
permitted. Any view about moral status that aspires to reflective
equilibrium with our deeply held moral convictions must confront the
abhorrence with which most thoughtful people would regard the
practical implications of treating humans with radical cognitive
disabilities as having even slightly lower moral status than the rest
of us.

A variety of approaches seek to address that abhorrence: by
identifying criteria for full moral status that include a wider range
of humanity
(Sec. 4.1);
by expanding the ways in which an individual can possess or achieve
full moral status without denying the primacy of individual attributes
(Sec. 4.2);
and by rejecting individual attribute accounts of moral status
(Sec. 5).

Several accounts identify attributes, such as the capacity to value or
care, that are shared by a greater proportion of human beings than
self-consciousness, practical rationality, autonomy, or moral
accountability. These accounts seek to recognize the full and equal
moral status of all, or almost all, human beings, including children,
and of adults with significant cognitive and psychological
disabilities. Among the more inclusive criteria proposed are the
capacities to communicate, or for minimal communication with other
humans (respectively, Berube 1996; Francis and Norman 1978); to value
or care (Jaworska 1999, 2007); and to give and receive love (Kittay
1999); to form relationships characterized by reciprocity of care
(Mullin 2011). Jaworska and Tannenbaum (2016 a, 2016b offer perhaps
the most detailed account that grounds moral status in the capacity to
form morally significant relationships. They maintain that “a
being merits higher moral status” if it has the capacity to
achieve, through a rearing relationship, “incomplete
realizations of activities characteristic of” humans with
typical psychological attributes (whom they call “self-standing
persons” (SSP)) (2016b, 1098). An actual rearing relationship is
not necessary, but only beings who can model Characteristic SSP
activities have the requisite capacity. This excludes humans
“capable of rudimentary conscious activity who nonetheless are
not yet capable of modeling SSP activities in any form” (2016b,
1101)—not only early fetuses but children and adults with the
most significant cognitive impairments, who will never have that
capacity.

These accounts are attractive in identifying attributes that may offer
a more intuitively appealing basis for moral status than practical
rationality or self-awareness, and in reducing, to varying extents,
the proportion of humanity excluded from full moral status. But
because they exclude some humans, and may include some non-human
animals, they do not fully capture commonsense views about moral
status and will be unacceptable to some philosophers. Moreover, these
alternative attributes do not resolve, but merely relocate, the
problem of accounting for the threshold and range features of full
moral status.

One attribute—the potential for any other individual
attribute held to suffice for full moral status—comes much
closer to full inclusion (Kumar 2008). But it faces three formidable
problems. As Joel Feinberg (1986) famously argued, the fact that
someone has the mere potential for an attribute does not warrant
treating him as if he actually possessed it. If potential has moral
significance, it cannot be directly inferred from the moral
significance of that which it actualizes. Further, some human beings
never have the potential for any individual attribute held to suffice
for full moral status, in any sense of “potential” that
would distinguish them from many non-human animals (McMahan 2008,
91–92). As debates about the moral status of the fetus suggest,
it is not at all clear when a being has the “potential”
for an attribute. The claim that someone has potential is a
counterfactual: in some other circumstances, perhaps a later
life-stage of the individual, the person would have the attribute.
This brings in difficult questions about the scope of such
counterfactuals. On a broad enough construal, every living being has
the potential to develop the relevant attributes in a sufficiently
different possible world, and so has full moral
status.[8]

Matthew Liao has argued for “the genetic basis for moral
agency” as a sufficient condition for full moral status that is
more plausible and inclusive than a potentiality criterion (Liao
2010). It accords full moral status to humans who have lost the
potential for agency, and to radically disabled humans who never had
such potential, in any conventional sense of that term. But it
includes these individuals at the cost of including almost all human
embryos—a cost many would consider excessive. Moreover,
Liao’s account requires a conceptually difficult, morally
uncertain distinction between genomes that have and lack “the basis
for moral agency” (e.g., Wasserman 2002; McMahan 2002, 2008).
Potentiality accounts face similar line-drawing problems; the question
is whether the shift from “potential” to “genetic basis” makes
those problems any more tractable. The genetic basis account also
shares what many would regard as a problem of “over
inclusiveness”—they confer moral status on early embryos, which
have the genetic basis for moral agency, at least as clearly as they
have the potential for it. To justify abortion, proponents of either
account must rely on a woman’s right to withdraw gestational
aid.

These challenges are inherited by two accounts that seek to base moral
status on the possession of a “modal property.” Shelley Kagan
(2016) and Jonathan Surovell (forthcoming) argue that beings who had,
or could have had, the psychological capacities of typical human
beings are their moral equals. According to both accounts, human
beings who lost, or never had, those capacities due to illness or
impairment still have the modal property that they could have had
them, and this property confers full moral status. That property is
not possessed by members of most other species, who could only have
acquired those capacities in quite distant possible worlds. As
Surovell puts it, “[d]isability but not species membership is a
matter of luck” (21).

These accounts face much the same challenge as Liao’s, of
determining whether a given being “could have” developed the
psychological capacities of human beings when their failure to do so
results from genetic differences. They also face the challenge posed
by members of other species capable of identity-preserving cognitive
upgrades (DeGrazia, 2016; McMahan, 2016). But perhaps the strongest
objection to grounding moral status in modal properties is raised by
DeGrazia: even if human beings with profound cognitive impairments are
aptly characterized as victims of bad luck, why does their victimhood
confer moral status? Surely that status cannot be justified as a
consolation prize for a near miss. While this objection does not
directly apply to the genetic-basis account, that account faces the
question of why the biological basis for morally significant
attributes itself has moral significance.

A second general way of accommodating the powerful intuitions about
the full moral status of all human beings is to recognize alternatives
to the actual possession of the status-conferring attributes. One
version of this approach treats human beings with radical cognitive
disabilities as, in effect, capable of acquiring the necessary
attributes by proxy, through their relationships with other human
beings. Thomas Scanlon (1998), for example, affirms the full moral
status of all human beings while basing full moral status (“the
requirement of justifiability”) on the individual capacity for
“judgment-sensitive” attitudes. Although he recognizes
that radically-impaired humans lack those attributes, he suggests that
they can acquire them vicariously, through trustees:

The tie of birth gives us good reason to want to treat [human beings
lacking the capacity for judgment-sensitive attitudes] “as
humans” despite their limited capacities. Because of these
limitations, the idea of justifiability to them must be understood
counterfactually, in terms of what they could reasonably reject if
they were able to understand such a question. This makes the idea of
trusteeship appropriate in their case, whether it is appropriate in
the case of nonhuman animals or not. It also indicates a basis on
which such a trustee could object to proposed principles. Severely
disabled humans have reason to want those things that any human being
has reason to want, insofar as those are things that they are capable
of benefiting from. (185–186)

Scanlon himself may understand trusteeship merely as a way of
realizing or respecting the full moral status of human beings with
radical impairments, a status that is based on “the ties of
birth.” Other philosophers, however, suggest that trusteeship
can secure full moral status by helping to satisfy criteria that could
not otherwise be met. Thus, Francis and Silvers (Francis 2009; Silvers
and Francis 2009) argue that cognitively normal human beings can
function as “mental prostheses” for radically impaired
ones:

[A]s a prosthetic arm or leg executes some of the functions of a
missing fleshly limb without being confused with or supplanting the
usual fleshly limb, so, we propose, a trustee’s reasoning and
communicating can execute part or all of a subject’s own
thinking processes without substituting the trustee’s ideas as
if it were the subject’s own. (485)

For example, trustees can help the subject fashion her own conception
of the good by carefully eliciting and extrapolating her attitudes and
preferences.

Francis and Silvers do not claim that the moral status of human beings
with the most significant cognitive impairments could rest on such
trusteeship, or on the potential for it. But it is useful to consider
two challenges facing their proposal, which they acknowledge. The
first is the question of authorship or authenticity: It is not clear
how a trustee’s reasoning could be said to “execute”
all, as opposed to part, of “a subject’s own
thinking.” It is not clear how the thinking can be the
subject’s if it was wholly executed by a trustee (Wasserman and
McMahan, 2012). The second challenge, shared by the notion of mental
prostheses and Scanlon’s notion of the vicarious expression of
judgment-sensitive attitudes, is the possibility of providing such
support for nonhuman animals—a possibility Scanlon leaves open
in the above passage. If it could be extended to animals, the
potential for such representation would ground the full moral status
of vast numbers of primates and other mammals. To close the
floodgates, it would seem necessary to argue that this support was
less feasible for intelligent animals, even domesticated ones, than it
was for radically impaired human beings. Clearly, an argument would be
needed that, in Francis and Silvers’ terms, it would be far more
difficult to fashion a mental prosthesis for the former.

A proxy approach also raises the difficult question of how the trustee
can acquire the moral and epistemic authority to speak for an
individual with radical cognitive disabilities. Legal systems assign
trustees or guardians to represent the “best interests” of
individuals too immature or impaired to make, or to have made, their
own judgments. But it is not clear how someone gets
“appointed” as a trustee for purposes of securing moral
status. Moreover, even those closest and most committed to an
individual with radical cognitive impairments may find it hard to
discern his interests, and distinguish them from their own
“judgment-sensitive” attitudes.

Another way of accommodating strong convictions about the full moral
status of all human beings grounds that status in actual relationships
between cognitively normal and radically-disabled human beings.
Because of their duties of partiality, the close relatives of
radically impaired individuals must treat them as if they had full
moral status. This could be regarded as an agent-relative status: for
close relatives and no one else, radically disabled humans actually
have full moral status. But because of the full moral status of those
close relatives, other human beings must respect their duty to regard
their disabled kin as full moral equals. They do not, however, have to
assume that duty themselves. Some proponents of individual-attribute
accounts—McMahan, for example—appear to take this view. In
contrast, some of the group-based accounts in the next section hold
that the “tie of birth” requires all cognitively
nondisabled human beings to accord full moral status to
radically-impaired human beings, regardless of their relationship. A
weaker version of this derivative or courtesy position does not claim
that a human being with radical cognitive disabilities actually has
full moral status even for close family members, merely that they must
treat her as if she did. This reduces somewhat (but does not
eliminate) the disparity between family members and third parties, but
only by downgrading the moral status of radically-impaired humans even
for their most significant others.

For some philosophers, either version of this view is unsatisfactory,
for two related reasons. First, it is too narrow, since it does not
offer radically impaired human beings complete moral equality. Only a
small subset of other humans need to treat them as moral equals; the
rest merely need to respect this special relationship. Second, it is
too contingent—a human with radical cognitive impairments owes
even his partial equality to the existence of close relationships. If
his parents and other relatives abandon him or die, he has only a very
tenuous claim to being treated by the rest of humanity any better than
a non-human animal with similar attributes.

We would suggest yet another “evidentiary” approach to
accommodating the conviction that every human being has full moral
status, one that calls for the adoption of a strong, even
“irrebuttable” presumption of full moral status for all
human beings. This approach is based on the difficulty of assessing
the cognitive potential of human beings, the powerful tendency to
underestimate the capacity and potential of human beings with any
degree of cognitive abnormality, and the terrible cost to individuals
who warrant but are denied full moral status. This approach can be
regarded as rule-consequentialist, in requiring that we sometimes
disregard our case-specific judgment because of the high probability
and substantial costs of error. But it may appeal to many who reject
rule-consequentialism as a general approach. At the same time, this
rationale for full moral status may seem uncomfortably grudging and
contingent. It appears to imply that, with sufficiently accurate
assessment tools and sufficiently reliable assessors, we could deny
moral status to many human beings whom we now are constrained to treat
as having it. Moreover, their exclusion would represent moral
progress.

Such a presumption of full moral status for humans with radical
cognitive disabilities could be given a more robust justification.
That justification would treat biological differences, species norms,
or “ties of birth” not as providing independent grounds
for full moral status, but as providing very strong reasons for
presuming it. Perhaps part of the reason we presume this is epistemic,
because it is so difficult to conclude that individuals who look human
really lack human capacities. But that is not the whole explanation.
When cognitively nondisabled humans encounter another being with human
appearance, they customarily respond to that being in ways they do not
to non-human animals; they use distinctive gestures, facial
expression, touch, speech, and other behavior. Such responses assume a
capacity for reciprocal exchange that may not always be present. But
even when it is not, those responses are not idle gestures. They may
enable communication, and provoke cognitive and social development,
that would otherwise not occur. Family members, friends,
professionals, and scholars who work with people who have cognitive
disabilities report that the more time they spend with individuals who
initially seemed unable to communicate or respond meaningfully, the
more they could discern about their interests, desires, and moods
(Brown and Gothelf 1996; Goode 1994). Indeed, those people often
display species-typical preferences in clothing, food, socializing,
and other activities. In sustained interaction with nondisabled humans
who treat them as members of the same moral community, cognitively
disabled individuals develop socially and psychologically along the
lines of other human beings. Treating people with cognitive
disabilities as if they had potential for typically human feelings,
desires and responses, then, can thus become self-fulfilling. This
approach offers a pragmatic (and consequentialist) justification for
presuming that all human beings have full moral status: not merely
because of the terrible costs of mistakenly denying that status, but
because treating fellow human beings as capable of joining our moral
community makes it more likely that they will be able to do so.

This proposal does not claim that such treatment could never be
effective if directed toward a dolphin or chimpanzee. But we have
stronger reasons to treat our fellow human beings this way, however
significant their cognitive disabilities. Our shared embodiment and
genetic endowment facilitate our treating them as having the capacity
or potential for typical human interaction and activity, and make it
likely that they will be more responsive to our treatment than a
non-human animal with similar cognitive abilities. Other intelligent
beings, differently embodied than we are, would have the same reasons
to treat their fellow beings this way. In recognizing such a
limited partiality, we do not treat species as having a moral
significance akin to that of families or even nations. Nor, clearly,
do we assume that human beings in particular have special moral
status.

Despite its resolute optimism, this proposal still excludes some human
beings from full moral status. It assumes a minimum level of social
responsiveness which is almost certainly lacking in human beings with
anencephaly, and perhaps lacking in human beings with other radical
cognitive impairments. Yet in its pragmatic justification of a limited
partiality towards members of the same species, it sets the stage for
views that give a more central role to species membership.

A number of philosophers have argued for the full moral status of all
human beings, without seeking to identify any attribute possessed by
all humans that would ground that status. These philosophers can be
roughly divided into two groups. Those in the first group regard
membership in the species Homo sapiens as sufficient for full
moral status and ground that status in a species-based attribute (See
Sec. 5.1).
For some philosophers within this first group, all homo sapiens
belong to a kind whose nature or norm it is to possess rationality or
similar attributes
(Sec. 5.1.1).
For others, all homo sapiens are connected through “ties of
birth” to other human beings
(Sec. 5.1.2).
For the former, any being of a kind whose nature it is to be
rational, etc. has full moral status; for the latter, any human
related by birth to other human beings has full moral status. Although
the two approaches pick out the same individual human beings, the way
in which they ground moral status gives them different implications
for the status of human beings with radical cognitive impairments.

The former way of grounding moral status gives it a wider
“writ,” because the individual’s moral status is not
based on his relationship to specific others. Rather, it is based on
the norm of a group to which she belongs. That norm demands
recognition by anyone, whether a member of the group or not, capable
of recognizing it. If human beings with radical cognitive impairments
have full moral status by virtue of belonging to a group with the norm
of rationality, a rational Martian, no less than a rational human,
should recognize the full moral status of humans with those
impairments. It might be possible to argue that the morally-relevant
norms of a group are not binding on those outside the group, but we
have not seen such an argument.

In contrast, ties of birth may not bind those lacking the same
biological connection; members of other species need not recognize the
full moral status of human beings with radical cognitive impairments.
In that sense, the moral status of those human beings is not as
“full” as that of other human beings, since it must be
recognized only by other humans. If full moral status is based on
duties of partiality toward members of the same group, it will be
group-relative, not binding on members of other groups.

The second type of group-based account
(Sec. 5.2)
acknowledges the moral significance of the group-based attributes
relied on by the first type of group-based accounts. But it denies
that the full and equal moral status of human beings can be grounded
in any specific attribute, even indirectly, that can be described in
morally neutral terms. These accounts regard “human being”
as a thick normative concept, grounded in language and social
practice, that is not necessarily coextensive with the biological
category of “Homo sapiens,” and that has moral content
that cannot be derived from any descriptive attribute associated with
it. The judgment that a being is human and therefore must be treated
respectfully does not consist of a value-neutral biological
classification and an argument that establishes the moral status of
beings so classified. The requirement for certain kinds of treatment,
and the prohibition of others, is part of the meaning of “human
being” and implicit in the recognition that a given individual
is a human
being.[9]
Proponents of these accounts thus reject the very attempt to identify
a criterial attribute possessed by all beings with the moral status of
cognitively normal human adults (Diamond 1978; Edwards 1997; Byrne
2000). These philosophers reject the treatment of cognitively
nondisabled adults as a paradigm for full moral status, and of
infants, young children, and radically cognitively disabled adults as
“marginal cases” whose moral status needs to be justified
by
extension.[10]

For both types of group-based accounts, the categorical nature of full
moral status is explained by the way in which that status is grounded.
Membership in the human species, a sufficient condition of that status
for accounts of both types, is a categorical rather than a continuous
“variable” (although there may be some vagueness or
ambiguity due to imprecise or conflicting membership criteria). And
for both types of account, the grounding of full moral status is the
same for all human beings, regardless of their individual
attributes.

5.1.1 Species Norms

On the first relational approach, some of the properties identified by
intrinsic-attribute accounts as sufficient for full moral status can
also play a distinct role in attaining it. Although, on this view,
self-consciousness and practical rationality are not necessary for
full moral status, they are the norm for human beings. This norm
cannot be understood statistically; it would not change if most or all
humans ceased to be self-conscious or practically rational. Rather,
the norm captures what is characteristic of the species. A normal
attribute is not, however, an essence that each member must possess.
Rather, it is a relational property: each individual has moral status
as the member of a group for which that attribute is the norm.
Scanlon, for example, claims that the class of those to whom we must
justify our actions “includes at least those beings who are of a
kind that is normally capable of judgment-sensitive attitudes”
(1998, 186).

Species-norm accounts focus on the human species, but they are not
limited to humans. Presumably, if we discovered that dolphins or
Martians were a species with a similar cognitive norm, members of that
species would possess full moral status whether or not they satisfied
that norm. We would be bound to recognize (if they could) the full
moral status of all dolphins or Martians, and they would be bound to
recognize the full moral status of all humans.

There may appear to be a tension in grounding full and equal moral
status in norms to which some but not all members conform. Even if the
norm of practical rationality gives all group members equal moral
status, it might seem that those members actually possessing that
attribute would be “more equal” than those lacking it. The
response to this concern, which we discuss in
Sec. 5.2,
is that those possessing the attribute have better fortune but no
greater moral status.

Not surprisingly, proponents of intrinsic attribute accounts, such as
McMahan, are unsympathetic with the claim that “facts about the
nature of some individuals could determine how other individuals that
lack that nature ought to be treated” (McMahan 2008, 85). Like
other critics, McMahan sees this claim as requiring a kind of
“moral alchemy” that transmutes factual claims about some
individuals into moral demands concerning others. But for those who
regard humanity as a “thick” concept
(5.2),
no alchemy is required. The concept of a human being is a normative
one, conferring rights on all those who fall under it and imposing
moral demands on those who understand and apply it.

5.1.2 (Co-)Humanity as a Special Relationship

A second kind of species-relationship claimed to confer moral status
is not between the individual human and the species norm, but between
the individual human and other human beings, in particular, those who
are cognitively normal. The claim is that human beings have a reason,
based on co-membership in the species, to regard each other as moral
equals. As Scanlon (1998) asserts,

[T]he mere fact that a being is ‘of human born’ provides a
strong reason for according it the same status as other humans. This
has sometimes been characterized as prejudice, called speciesism. But
it is not prejudice to hold that our own relation to these beings
gives us reason to accept the requirement that our actions be
justifiable to them. (185)

This position grounds full moral status in the kinship of all human
beings—what used to be called “the family of man.”
Although this kinship currently depends on birth to a human mother, it
is shared by all human beings and does not vary with degree of
consanguinity.[11]

This approach avoids the questionable notion of a species norm as a
source of moral status. But unlike a species-norm account, it requires
no one but human beings to recognize the full moral status of all
humans. On the species norm account, McMahan (2002) observes,

[I]ntelligent and morally sensitive Martians would be required to
treat severely retarded human beings in the same way they would be
required to treat us. … But if the reason we have to accord the
severely retarded the same moral status as other human beings is that
we are related to them through the ‘tie of birth,’ then
Martians would not have this reason. (217)

This is a practically insignificant limitation at present, but an
expressively significant one for those who insist that moral status be
universally recognized.

A defender of a human kinship approach might readily accept this
limitation, especially since we and the Martians would still be
constrained by the attachments of the cognitively normal members of
the other species to their radically impaired relations (as discussed
in
Sec. 4.2
above). But she would still have to defend the claim that
co-membership in the species established the sort of kinship that
required even this species-relative full moral status. McMahan (2002)
argues that even if membership in some groups, like nations, could
confer full and equal status on its members, membership in the same
species could not:

Unlike membership in a nation, membership in a species is not a focus
of collective identity. Being human does not significantly
differentiate us from anything else; it therefore fails to engage our
pride or enhance our sense of identity. Just as no one’s sense
of identity is enlarged by the recognition that one is an animal
rather than a plant, so no one’s sense of identity is
importantly shaped by an awareness of being human rather than being,
for example, a rabbit. (221)

The defender of a “ties of birth” account could respond in
two ways. First, she might deny that species identity and pride were
necessary to ground the full moral status of species members. Rather,
that status was grounded in similarities among human beings, even
radically disabled ones, that arose from their distinctive embodiment
and that created a strong sense of fellowship (among those
self-conscious enough to feel fellowship) overshadowing even vast
differences in mental capacity. These similarities include ways of
feeling, communicating, moving, and reacting to and interacting with
other members of the species. These affinities are refracted by
culture, members of other species share some of them, and not all
members of the species—even cognitively normal ones—share
all of them. Nevertheless, they may be a distinctive enough ensemble
to provide a basis for partiality. Or a defender might argue, as
Bernard Williams (2006) does (see
Sec. 5.2),
that species-identity and pride could play a role in human
fellowship now obscured by the lack of a suitable comparison class.
Although, as Robert Nozick (1974) observed, no contemporary human
boasts about having an opposable thumb or speaking a language, our
sense of species pride and identity might crystallize in the presence
of another advanced species, which would highlight our distinctive
shared history and achievements.

Standing alone, however, both responses seem vulnerable to the claim
that similarities associated with species membership may explain, but
cannot justify, the treatment of all other human beings as moral
equals. Why should a sense of fellowship, however strong, be a source
of moral status? If our sense of fellowship reflected what mattered
morally, why wouldn’t we feel greater fellowship with
McMahan’s intelligent, morally sensitive Martian than with a
human infant whose developmental disabilities make him apparently
unresponsive to other humans?

One response is that what justifies intra-species partiality is not
the capacity to share but the capacity to benefit. Thus, Gunnarson
(2008) suggests that members of our own species have a capacity to
derive unique, intrinsic benefits from their relationship to other
human beings. Reliance on such a capacity may provide an intuitively
more appealing basis for full moral status than biologically-based
similarities. But it might still deny full moral status to some
humans—not only anencephalic infants but others lacking the
capacity to benefit from relations with other humans. Moreover, some
non-human animals, especially domesticated ones, may derive immense
benefits that are intrinsic and unique to their relationship to humans
(Townley 2010). And the members of other cognitively advanced species
might well benefit in highly specific, possibly unique ways, from
interaction with human beings.

To explain the moral significance of species co-membership, some
philosophers embrace a strongly anthropocentric view, which denies
that we can step outside of our humanity to assess the moral status of
the world’s inhabitants. On this view, the concept of a human
being is prior to, and inseparable from, that of a
person.[12]
As Stephen Mulhall (2002) argues:

[O]ur concept of a person is an outgrowth or aspect of our concept of
a human being; and that concept is not merely biological but rather a
crystallisation of everything we have made of our distinctive species
nature. To see another as a human being is to see her as a
fellow-creature—another being whose embodiment embeds her in a
distinctive form of common life with language and culture, and whose
existence constitutes a particular kind of claim on us. (7)

This view, which, following Williams (2006), we will call
“humanist,” has two variants. The first, per Mulhall, is
linguistic or conceptual, influenced by Wittgenstein (1958). We come
to understand notions like thinking, deciding, and feeling in terms of
the behavior of other human beings, and, although we can attribute
some of these capacities or states to other beings, it is only by
extension or analogy (Hanfling 2001). We also learn the appropriate
ways of acting toward fellow human beings in learning the very
concept: for example, human beings are to be named, and not eaten even
when they are dead. We do not conclude that human beings must
be treated this way; the recognition that they must is already part of
the meaning of the concept (Diamond 1978; Gleeson
2008).[13]
This “thick” concept of human being is not a biological
one, and need not have the same extension as the class of Homo
sapiens[14].
For some humanists of this type, a newly-created embryo is not a
human being, and it is not part of the meaning of human being that the
life of a newly-fertilized embryo must be protected to the same extent
as the life of a newborn human infant (Crary 2007). But the very fact
that other humanists do regard early embryos as human beings
suggests the need for an account of how such a deeply-embedded concept
can be so vague or debatable at the margins.

Because of the role of our language and concepts in our moral
understanding, the justification and criticism of our moral practices
can only be internal to them, on humanist accounts. As Byrne
maintains,

reason operates in ethics properly when it functions immanently.
Offering a sound moral argument in criticism of any one of our moral
practices would be a matter of drawing upon insight from some other
part of our moral life. (2000, 70–71)

The case against eating animals, for example, cannot be made by citing
attributes they share with us, but only by exposing tensions or
contradictions with our other practices (Diamond 1978). Presumably,
similar but more acute tensions would confront any view of humanity
that excluded some biological human beings or denied some of them full
moral status, making racism and sexism untenable without placing any
pressure on the concept of humanity itself.

The second variant denies the possibility of an impartial basis for
assessing moral status. To attempt to grade or evaluate the
world’s inhabitants in absolute terms is to treat the universe
as having a point of view—the perspective of a deity or a
utilitarian Ideal Observer (Williams 2006). Without such a vantage
point, human beings can judge the rest of the world only in terms of
their own concerns, values and civilization. Indeed, it is only in
those terms that we value those characteristics, like rationality and
self-consciousness, regarded by individual-attribute theorists as
criteria for full moral status (Grau, 2016). Our humanity thus gives
us an indispensable frame of reference for evaluating the rest of the
world. It also grounds a defensible partiality toward each other that
has little in common with racism or sexism. Not only do almost all of
us accept naked appeals to the humanity of another being, as opposed
to her sex or race, as the basis for action or restraint, we appeal to
humanity in rejecting racism and sexism. Naked appeals to race or sex,
unsupported by claims about morally relevant attributes, are rarely
made by the most unapologetic racist or sexist. The “human
prejudice” is more akin to the affinity and loyalty of
participants in a shared culture. If it is difficult to see “the
human prejudice” this way, it may be because “[h]uman
beings do not have to deal with any other creature that, in terms of
argument, principle, worldview, or whatever, can answer back”
(Williams 2006, 148). A distinctively human “culture” is
both pervasive and barely visible in a world that offers no rivals.
Williams does not claim that our commitment to that culture would
necessarily trump an appeal to participate in a more advanced
universal community and relinquish cherished but parochial aspects of
our own culture. Nevertheless, that commitment would give us a morally
defensible reason, not just a prejudice, against such
assimilation.

Humanist accounts recognize that species norms have moral
significance, but they do not assign them the criterial role they play
in accounts that ground moral status in relational attributes. In the
passage from which we quoted earlier, Mulhall regards radically
disabled humans as suffering a grave misfortune in lacking
characteristically human capacities:

We do not strive (when we do strive) to treat human infants and
children, the senile and the severely disabled as fully human because
we mistakenly attribute capacities to them that they lack, or because
we are blind to the merely biological significance of a species
boundary. We do it (when we do) because they are fellow human beings,
embodied creatures who will come to share, or have already shared, in
our common life, or whose inability to do so is a result of the shocks
and ills to which all human flesh and blood is heir—because
there but for the grace of God go I. (Mulhall 2002, 7)

For a humanist like Mulhall, the capacity to participate in
distinctively human forms of life is neither necessary nor sufficient
for full moral status (as McMahan (2005) appears to assume). That
status is established merely by our recognition of an individual as a
human being, heir to the same “shocks and ills” as we are.
Human beings with radical cognitive disabilities suffer “grave
misfortune,” not reduced status if they are unable to share in
the distinctive forms of our common life in which their embodiment has
“embedded” them. Non-human animals with similar attributes
have lower moral status but suffer no comparable estrangement or loss.
Their participation in their own species’ distinctive forms of
life—if there are any—does not depend upon, and might well
be impaired by, their possession of the cognitive attributes of normal
adult humans.

A critic might concede that we in fact hold these divergent attitudes
toward humans and non-human animals but would question their moral
significance: why should we regard the congenital absence of certain
capacities as a tragedy for the individual lacking them if
and only if that individual is human (McMahan 1996)? A humanist would
respond that the question itself reveals that the critic simply is not
clear on the concept of “human being”—a concept that
includes the notion of a common life, based on shared embodiment, from
which radically impaired humans are excluded.

Humanists are wary of grounding the full moral status of
radically-impaired humans in their relationship to a species-norm like
rationality. Thus, Byrne (2000) argues that appeal to the rational
nature of human beings as the basis for respect is too reliant on
external justification and too narrow. It is too reliant on claims
about the respect owed to beings that are rational-by-nature, which
Byrne doubts are any more self-evident or plausible than claims about
the respect owed human beings. It is too narrow because it ignores
other aspects of humanity that make the concept of “human
being” so rich and powerful.

The position of humanists on the species-relativity of moral status is
uncertain. Given the critical role they assign to “the
distinctive form of common life” of human beings for moral
recognition and obligation, it is not obvious that Mulhall or Diamond
would require an intelligent Martian to recognize and respect the
moral status of cognitively normal human beings, let alone of human
beings with radical cognitive impairments. Indeed, it is not clear how
humans could confidently impute intelligence to Martians if their
embodiment was sufficiently different from ours, let alone whether we
could regard them as subject to moral obligations of any kind.
Similarly, it is not clear whether Mulhall and Diamond would hold that
humans were required to treat Martians as moral equals, even if they
could attribute intelligence and moral sensitivity to them. The role
they assign to distinctively human forms of life raises doubts about
the possibility of mutual comprehension, recognition, and respect.

In contrast, Williams’ account, and others less wedded to a
Wittgenstinian view of language and concepts, can more readily address
the prospect of close encounters with other intelligent beings.
Williams himself considers such encounters, and acknowledges the
possibility of mutual recognition, though he thinks it might be
reasonably qualified by partiality towards the members of one’s
own species and its culture.

These two humanist accounts leave critical questions about the
boundaries of the thick concept of “human being.” Does
that concept encompass early embryos, or human-like beings produced by
a future synthetic biology? Can we answer such questions in terms of
the “fit” of a proposed boundary with the other beliefs
and practices associated with the concept, or are such questions
decided less self-consciously by gradual shifts in our actual
practices? Without a better sense of how boundary questions can be
resolved, it is not clear how humanist accounts will meet the
challenges of exclusion.

There seems to be little prospect for consensus on the moral status of
people with the most severe cognitive disabilities. There are sharp
disagreements about how, or even whether, the moral status of humans
can be grounded, and about the weight to be given our strongest and
most considered, moral convictions. Accounts that ground full moral
status in an individual’s possession of psychological attributes
inevitably exclude some portion of humanity, and appear to have
implications for the treatment of the excluded human beings that few
of us are willing to accept. Those implications are avoided by
accounts that ground full moral status in our species
membership—in the nature of the species or in our biological
relationships to other members. Those implications are also avoided by
accounts that deny the need to ground the moral status of human beings
in any attribute we or our group possesses. But these ways of avoiding
exclusion have significant costs. They require a strong partiality
toward those with shared biological features, physical appearances, or
origins, a partiality that conflicts with equally strong, if more
abstract convictions about the justification for our conduct towards
others. And they leave deep uncertainty about the moral constraints on
our treatment of other living beings and about the boundaries of
humanity itself.

Despite the serious challenges facing both approaches, and the
formidable obstacles to reaching any sort of consensus, the discussion
about the moral status of human beings with radical cognitive
disabilities is a central one for applied ethics. It needs to
continue.

Savulescu, J., 2009. “The Human Prejudice and the Moral
Status of Enhanced Beings: What Do We Owe the Gods?” in
Human Enhancement, J. Savulescu and N. Bostrom (eds.), New
York: Oxford University Press, 211–250.